Distribution of intraocular pressure among healthy Pakistani.

Because the course of glaucoma is often an insidious one and most cases remain asymptomatic until the visual field has been clearly diminished, the frequency distribution of intraocular pressure (IOP) is important from both an academic and clinical viewpoint. However, diagnostically, glaucoma is a disease suited to a preventive approach. Due to differences in intrinsic constitution, diet and environmental conditions, there is a clear need for well collected population-based IOP data in different countries. In the present study, after controlling for the factors that can effect IOP, we investigated the distribution of intraocular pressure in 7201 healthy subjects of both sexes of Karachi, Pakistan. In both sexes, distribution of IOP slightly skewed towards the higher values. In males and females, 85.1% and 82.2% individuals ranged from 11 to 18 mmHg, 4.3% and 3.2% ranged from 8 to 10 mmHg, 7.1% and 11.2% ranged from 19 to 21 mmHg, respectively. Ocular hypertension (IOP > 21 mmHg) was found in 3.5% males and 3.7% females. Intraocular pressure increased with age in both eyes of both sexes. The averages per decade increase were 0.3 mmHg and 0.5 mmHg in male and female respectively. This study reports that an average per decade increase, women have 0.4 mmHg higher IOP than men. The male-female difference was not statistically significant until the age groups reached 31-40 years, after which the differences became significant. Right and left eyes IOPs were found to be 14.3 +/- 0.17 and 14.4 +/- 0.12 mmHg in male and 14.6 +/- 0.14 and 14.8 +/- 0.15 mmHg in females respectively. This survey shows that mean IOP of Pakistani population is similar to the IOP found in other epidemiologic investigations; the prevalence of ocular hypertension, however, seems to be slightly higher. Knowledge of the normal level of IOP in various age groups of both sexes will help to screen glaucoma.

Effect of seasons upon intraocular pressure in healthy population of China.

Studies have been shown that intraocular pressure (IOP) shows a seasonal variation, but amount of change differs from study to study. The variability in their results may be due to negligence of factors that can affect IOP. Due to differences in environmental conditions of China than other countries, we investigated seasonal variations in IOP of 103 healthy male Chinese of Shanghai. IOP was measured each month over the course of fourteen months with the Goldmann applanation tonometer. The average intraocular pressures in the winter months were higher than those in the spring, summer, and autumn months. The IOP difference between winter and summer months was found to be 1.4 +/- 0.7 mmHg. This study confirms that season influences IOP. As compared to other nations, effect of seasons on IOP seems to be somewhat less pronounced in Chinese. The possible mechanisms, responsible for the seasonal variation of intraocular pressure, are also postulated.

Diurnal variation of intraocular pressure in normal and ocular hypertensive subjects of China.

This study evaluated the distribution of Intraocular pressure (IOP) levels in 67 normal and 59 ocular hypertensive (OHT) subjects during the day after placing control on all those factors that can affect IOP. The IOP was measured with the Goldmann applanation tonometer. All the subjects were examined according to standard protocols. Both in the normal and OHT subjects, the peak of mean IOP appeared in the morning when the subjects woke up and the trough of mean IOP occurred between 2 a.m. to 4 a.m. The mean diurnal variation were (mean +/- sem) 2.9 +/- 0.7 and 3.5 +/- 0.7 mmHg in the normal and in OHT subjects, respectively. Ninety-four percent of the normal subjects and sixty-eight percent of the OHT subjects exhibited a similar diurnal behaviour in both eyes. The IOP variation did not correlate with the variations of blood pressure. The diurnal variation of IOP, found in Chinese, is lower than in other nations. The clinical importance of findings that the peaks of IOP occur in the early morning, raised a serious question as to the necessity of extending the diurnal IOP curves beyond the usual working time (JPMA 46:171, 1996).

[Corneal topographic analysis of small incision in cataract surgery].

OBJECTIVE: The study was designed to investigate the corneal topographical and corneal curvature changes of small incision in cataract surgery. METHODS: 38 eyes of 36 patients who had undergone small incision cataract surgery were followed up at one week and one, three, six and twelve months postoperatively by corneal topography and keratometer. RESULTS: At one week postoperatively, there was slight steeping or flattening at the center and peripheral cornea, but the change was recovered to the preoperative state after one month. No significant changes had been observed after a long-term observation. The result of keratometer was different from that of topography. CONCLUSIONS: It is clearly demonstrated that smaller wound incision produces less astigmatism, faster postoperative recovery and more stable refraction. The results of corneal topography reflect curvature changes more reliably and precisely than that of keratometer, and topography is of great value in cataractous surgical evaluation.

The effect of physical fitness on intraocular pressure in Chinese medical students.

BACKGROUND: Virtually all the tissues and systems of the human body have been shown to be responsive to programs of exercise. Regarding the relationship between physical fitness and intraocular pressure (IOP), the existing literature is controversial with some associations inconsistent. In one study, IOP values were not dependent upon changes in physical fitness. In contrast to this, another study demonstrated that physical fitness significantly reduces intraocular pressure levels. In recent years it has been noted that intraocular pressure is a dynamic function and is subject to many influences both acutely and over the long term. The variety of results of previous studies may have come from several factors which can affect intraocular pressure. The present study was planned to investigate the effects of physical fitness on intraocular pressure in Chinese medical studies, after elimination of other affecting factors. METHODS: Forty medical students were categorized into control and experimental groups, each consisting of 20 subjects. The experimental group took a supervised exercise program for 10 weeks. Physical fitness was evaluated by measurement of maximum oxygen uptake with a Beckman O2 analyzer. Intraocular pressure was measured with the Goldmann applanation tonometer. RESULTS: After exercise training, the experimental group showed a marked increase in physical fitness. The difference of IOP between the control and experimental groups before exercise conditioning was 0.3 +/- 0.1 mmHg (P > 0.05). After 10 weeks, this difference increased to 1.1 +/- 0.4 mmHg (p < 0.05). CONCLUSIONS: This study concludes that physical fitness reduces intraocular pressure. Whether exercise conditioning has a role as a nonpharmacologic approach or as an addition to medical therapy must be left to future investigations.

The effect of exercise training on physical fitness and plasma lipids in young Chinese men and women.

BACKGROUND: The mortality from coronary heart disease (CHD) has been steadily increasing in many parts of the world. Measures to reduce the incidence of CHD were initially addressed mainly to middle aged and elderly population groups, but for effective prevention of CHD, measures addressed to younger age groups are also necessary. Moreover, differences between male and female plasma lipid changes after exercise training are not known exactly. METHODS: The concentrations of plasma lipids, before and after regular physical exercise training for 12 weeks, were analyzed in 25 male and 25 female medical students of the same age group. Physical fitness was evaluated by the measurement of maximum oxygen uptake. RESULTS: Results indicated that plasma tri-glyceride, HDL-cholesterol, LDL-cholesterol and VLDL-cholesterol differences between the before-and-after exercise were significant (p < 0.05) in males while the differences of plasma total cholesterol were found to be insignificant. In females there were no significant changes in the plasma lipids levels. In both males and females, the marked increase in maximal O2 uptake after exercise training indicated an improvement in physical fitness. CONCLUSIONS: This study concludes that a short-term exercise program can improve plasma lipid and lipoprotein patterns more in males than in females. It also suggests that daily physical exercise may be an important prevention for cardiovascular diseases in later life, so it is essential to establish a life style with optimum nutrition and physical activity in both the young and in adults of all ages.